Tokyo Sewage Treatment Facility as Radiated as Fukushima Evacuation Area

Tokyo Sewage Treatment Facility as Radiated as Fukushima Evacuation Area
Yomiuri Shimbun: 都の下水処理施設で高放射線量…避難区域に匹敵
June 8, 2011

A test of the air quality inside the sewage treatment plant in Ōda, Tokyo revealed that it is emitting about 2.7 microsieverts of radiation per hour.

That is nearly equal to the radiation level in the town of Iitate, which is part of the Fukushima evacuation area. According to the Ministry of Education, Culture, Sports, Science and Technology, this is the first time such a high level of radiation has been found inside the city. Radioactive material is thought to be inside the sludge, but the city also said “The test was done inside the building. There are no problems in the surrounding area.” They did not publicly announce their findings because they didn’t want any misunderstanding to trigger panic.

According to the capital, the sewage treatment facility is the “southern sludge plant,” one of the two locations in the city where sludge is collected and burned. The ashes are buried in Tokyo Bay among other places. According to a May test, those ashes contain 10,540 becquerels of cesium per kilogram.

When the city measured radiation on June 6, it found the airborne radiation in the facility was 2.693 microsieverts per hour. Hourly radiation in Iitate that same day was 2.86 microsieverts. If this radiation accumulated in a linear fashion for a year, it would rise to 23.6 millisieverts, which is higher than the 20 mSv standard for evacuating an area.

The city said that because the radiation outside the facility was only 0.038 microsieverts per hour, area residents should not worry about their health. Workers at the facility were again encouraged to wear masks and gloves.

Original/原稿:
都の下水処理施設で高放射線量…避難区域に匹敵

 東京都大田区の下水処理施設内の空気中から、毎時約2・7マイクロ・シーベルトの放射線量が検出されていたことが、都の調査で分かった。

 計画的避難区域の福島県飯舘村の放射線量と同程度で、文部科学省によると、都内でこれほどの放射線量が検出されたのは初めて。放射性物質を含む汚泥の影響とみられるが、都は「検出場所は屋内。敷地の境界では問題なく、誤解を招く恐れがある」とし、調査結果を公表していなかった。

 都によると、この施設は都下水道局の「南部スラッジプラント」で、都内2か所の下水処理場で発生した汚泥を集めて焼却し、灰を東京湾に埋め立てるなどしている。都の5月の調査では、この施設の焼却灰から1キロ・グラム当たり1万540ベクレルの放射性セシウムを検出していた。

 今月6日、都が放射線量を測定したところ、焼却灰の仮置き場所となっている棟内の空気中で毎時2・693マイクロ・シーベルトを検出した。同じ日の飯舘村での放射線量は2・86マイクロ・シーベルトだった。同施設内の放射線量を1年分に単純換算すると約23・6ミリ・シーベルトとなり、計画的避難区域の対象となる年間積算量の20ミリ・シーベルトを上回る。

 都は、施設内の別の場所では毎時0・038マイクロ・シーベルトにとどまっていることなどから、周辺住民らへの健康被害の恐れはないと説明。作業員には手袋やマスクの着用を改めて指示したとしている。
(2011年6月8日14時33分 読売新聞)

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